lis3: fix regression of HP DriveGuard with 8bit chip

Commit 2a7fade7e03 ("hwmon: lis3: Power on corrections") caused a
regression on HP laptops with 8bit chip.  Writing CTRL2_BOOT_8B bit seems
clearing the BIOS setup, and no proper interrupt for DriveGuard will be
triggered any more.

Since the init code there is basically only for embedded devices, put a
pdata check so that the problematic initialization will be skipped for
hp_accel stuff.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Cc: Samu Onkalo <samu.p.onkalo@nokia.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 6 deletions

diff --git a/drivers/misc/lis3lv02d/lis3lv02d.c b/drivers/misc/lis3lv02d/lis3lv02d.c
index b928bc14e97b..8b51cd62d067 100644
--- a/drivers/misc/lis3lv02d/lis3lv02d.c
+++ b/drivers/misc/lis3lv02d/lis3lv02d.c
@@ -375,12 +375,14 @@ void lis3lv02d_poweron(struct lis3lv02d *lis3)
          *      both have been read. So the value read will always be correct.
          * Set BOOT bit to refresh factory tuning values.
          */
-        lis3->read(lis3, CTRL_REG2, &reg);
-        if (lis3->whoami ==  WAI_12B)
-                reg |= CTRL2_BDU | CTRL2_BOOT;
-        else
-                reg |= CTRL2_BOOT_8B;
-        lis3->write(lis3, CTRL_REG2, reg);
+        if (lis3->pdata) {
+                lis3->read(lis3, CTRL_REG2, &reg);
+                if (lis3->whoami ==  WAI_12B)
+                        reg |= CTRL2_BDU | CTRL2_BOOT;
+                else
+                        reg |= CTRL2_BOOT_8B;
+                lis3->write(lis3, CTRL_REG2, reg);
+        }
 
         /* LIS3 power on delay is quite long */
         msleep(lis3->pwron_delay / lis3lv02d_get_odr());